Computer-assisted surgery (CAS) systems typically have a tracking device to track in space an object involved in a surgery, such as an implant or a surgical instrument. A computer system for outputting information related to the object being tracked is also generally used. Computer-assisted surgery (CAS) systems may display information about the object being tracked on a single displaying device, with or without images acquired by the CAS system.
Some more recent CAS systems involve imageless tracking as opposed to commonly used image-based systems. The displaying device is however typically located outside the surgical sterile field and away from the surgical table. With this configuration, the medical personnel involved in the surgery, or present in the room, may view the information being displayed. A user performing or involved the surgery must move his/her head and/or divert his/her sight from the surgical field of view or the location at which the surgery is being performed in order to look at the displaying device. Possible involuntary movements of the arms and hands of the user may occur at this moment and create an undesired displacement of the object being manipulated or an error in performing actions required during surgery.
The displaying device of typical CAS systems is also for the use of everyone in the operation room. The information displayed is the same for everyone and not necessarily targeted at a specific task of a specific viewer/user.